After reaching the Pacific Ocean, the Corps of Discovery camped at Fort Clatsop in the winter of 1805–1806. The parks also preserve several landing sites on the north bank of the river in Washington, and other sites in Oregon.

This map outside the Lewis and Clark National Historical Park visitor center points visitors to the various historical landmarks within the park, including the reconstructed Fort Clatsop.

The federal park began as Fort Clatsop National Memorial which was established on May 29, 1958. The memorial was listed on the National Register of Historic Places on October 15, 1966. On October 30, 2004, it was redesignated Lewis and Clark National Historical Park with expanded jurisdiction over multiple sites,[4] including:

Ecola was the site of the Corps of Discovery's 1806 trek over difficult terrain to see a beached whale. Today, it features several miles of hiking trails through old growth forest, and several beaches. Haystack Rock and the Needles are visible from many sites in the park. Much of the 1985 film The Goonies was filmed there, and the final scenes of the 1991 film Point Break were filmed at Indian Beach in the park.

Fort Stevens, with its 3,700-acre (1,500 ha) park, offers exploration of history, nature, and recreational opportunities. The fort was the primary military defense installation in the three fort Harbor Defense System at the mouth of the Columbia River (Fort Canby and Fort Columbia were other two).

Sunset Beach is the terminus of the Fort To Sea Trail, which begins in Fort Clatsop. Sunset Beach also provides visitors with direct access to the Pacific Ocean with expansive views from Cape Disappointment to the north and Ecola State Park to the South.

Cape Disappointment, formerly known as Fort Canby State Park, is a 1,882-acre (762 ha) camping park on the Long Beach Peninsula, fronted by the Pacific Ocean. The park offers 27 miles (43 km) of ocean beach, two lighthouses, an interpretive center and hiking trails. The Cape Disappointment Historic District was listed on the National Register on August 15, 1975.

Fort Columbia is an old coastal artillery post along the north side of the Columbia river outlet. At 593 acres (240 ha), the park includes an interpretive center focused on the fort and regional history.